JP3785458B2

JP3785458B2 - Transmission electron microscope and stereoscopic observation method

Info

Publication number: JP3785458B2
Application number: JP2002336392A
Authority: JP
Inventors: 敬義丹司
Original assignee: Nagoya University NUC; Tokai National Higher Education and Research System NUC
Current assignee: Nagoya University NUC; Tokai National Higher Education and Research System NUC
Priority date: 2002-11-20
Filing date: 2002-11-20
Publication date: 2006-06-14
Anticipated expiration: 2022-11-20
Also published as: US7012253B2; EP1426998A2; JP2004171922A; US20040144923A1

Description

【０００１】
【発明の属する技術分野】
本発明は、透過型電子顕微鏡及び立体観察法に関する。
【０００２】
【従来の技術】
従来、透過型電子顕微鏡を用いた立体観察法としては、ＣＴ法及びステレオ法が広く使用されている。ＣＴ法は、一つの試料を０度から１８０度回転させるとともに、前記角度範囲内において試料の所定部分の投影画像を多数枚撮影し、得られた画像を計算機処理することによって前記所定部分の３次元構造を得、立体観察を可能ならしめるものである。ステレオ投影法は試料を回転させ、前記試料の傾きが視差角だけ異なる２枚の像を撮影し、現像及び焼き付けした後にステレオビュアーなどを用いることにより立体観察するものである。
【０００３】
【発明が解決しようとする課題】
しかしながら、前記ＣＴ法においては計算機処理に時間を要し、前記試料の変化を実時間で観察することができないという問題があった。また、前記ステレオ投影法においては前記試料の回転という操作に加えて、現像及び焼き付けという操作が加わり、これら一連の操作には数十分を要することから、この場合においても前記試料の変化を実時間で観察することができないという問題があった。
【０００４】
本発明は、試料の変化を実時間で観察できる透過型電子顕微鏡及びこの顕微鏡を用いた立体観察法を提供することを目的とする。
【０００５】
【課題を解決するための手段】
上記目的を達成すべく、本発明は、
電子線照射源と、
前記電子線照射源の前方に設けられ、前記電子線照射源から発せられた電子線を偏向して得た第１の電子線を、試料面の所定部分に対して第１の角度で照射するとともに、前記電子線照射源から発せられた前記電子線を偏向して得た第２の電子線を、前記試料面の前記所定部分に対して前記第１の角度と異なる第２の角度で照射させるための偏向装置と、
前記第１の電子線による第１の像及び前記第２の電子線による第２の像を結合させ、前記試料面の前記所定部位の像を立体的に表示する３次元画像表示装置とを具え、
前記偏向装置は、一対のフィラメントと、この一対のフィラメントの外方に設けられた一対のアース電極とからなる電子線台形プリズムを含み、
さらに、前記電子線照射源及び前記電子線台形プリズムと、前記３次元画像表示装置との間において、前記第１の電子線による前記第１の像、及び前記電子線照射源から発せられた第３の電子線により、前記試料面を介することなく得た第３の像を重ね合わせた第１の電子線ホログラムと、前記第２の電子線による前記第２の像、及び前記第３の像を重ね合わせた第２の電子線ホログラムとを形成するための結像装置を具えることを特徴とする、透過型電子顕微鏡に関する。
【０００６】
また、本発明は、
電子線照射源から電子線を発射する工程と、
前記電子線照射源の前方に設けた偏向装置によって前記電子線を偏向して得た第１の電子線を、試料面の所定部分に対して第１の角度で照射するとともに、前記偏向装置によって前記電子線を偏向して得た第２の電子線を、前記試料面の前記所定部分に対して前記第１の角度と異なる第２の角度で照射する工程と、
３次元画像表示装置によって、前記第１の電子線によって得られた第１の像及び前記第２の電子線によって得られた第２の像を結合させ、前記試料面の前記所定部位の像を立体的に表示する工程とを具え、
前記偏向装置は、一対のフィラメントと、この一対のフィラメントの外方に設けられた一対のアース電極とからなる電子線台形プリズムを含み、前記フィラメントに印加する電圧の極性を切り替えることにより、前記電子線の偏向方向を変化させ、前記第１の電子線及び前記第２の電子線を形成し、
さらに、前記電子線照射源及び前記電子線台形プリズムと、前記３次元画像上表示装置との間において結像装置を設け、前記第１の電子線による前記第１の像、及び前記電子線照射源から発せられた第３の電子線により、前記試料面を介することなく得た第３の像を重ね合わせた第１の電子線ホログラムと、前記第２の電子線による前記第２の像、及び前記第３の像を重ね合わせた第２の電子線ホログラムとを形成する工程を具えることを特徴とする、立体観察法に関する。
【０００７】
本発明者らは上記目的を達成すべく鋭意検討を実施した。その結果、所定の電子線照射源より発せられた電子線を偏向させて２種類の電子線を形成し、それぞれ異なる角度で試料面の同一部分に入射させることにより、前記２種類の電子線に対応させた２種類の像を得、これらを結合することによって、前記試料面の前記部分を３次元的に観察できることを見出したものである。すなわち、前記試料面の前記部分に対して、前記２種類の電子線を異なる角度で照射するようにしているので、前記２種類の像は、前記角度に対応した視差角だけ異なる２種類の像に相当する。したがって、これらの像を結合して、所定の３次元画像表示装置上に表示するようにすれば、前記部分の立体表示が可能となり、立体観察が可能となるものである。
【０００８】
また、本発明によれば、上述したＣＴ法などのような複雑な計算機処理を必要とせず、さらにステレオ投影法などのように現像及び焼き付けなどの操作を必要としないので、前記試料面の観察に要するタクトタイムは前記第１の電子線及び前記第２の電子線の、前記試料面に対する照射時期のずれ（時間間隔）に依存する。しかしながら、前記照射時間のずれは限りなく小さくすることができ、所定の外部信号などと同期させることにより、１００分の１秒オーダ程度まで簡易に低減することができる。したがって、前記試料面の観察を実時間で実行することができるようになる。
【０００９】
また、本発明では、前記偏向装置は、一対のフィラメントと、この一対のフィラメントの外方に設けられた一対のアース電極とからなる電子線台形プリズムを含み、前記フィラメントに印加する電圧の極性を切り替えることにより、前記電子線の偏向方向を変化させ、前記第１の電子線及び前記第２の電子線を形成する。これによって、前記試料面の同一部分に対して異なる角度で照射すべき、前記第１の電子線及び前記第２の電子線を簡易に形成することができる。したがって、前記試料面の立体観察を簡易に行なうことができるようになる。
【００１０】
さらに、前記電子線照射源及び前記電子線台形プリズムの前方において結像装置を設けることにより、前記第１の電子線による前記第１の像、及び前記電子線照射源から発せられた第３の電子線により、前記試料面を介することなく得た第３の像を重ね合わせた第１の電子線ホログラムと、前記第２の電子線による前記第２の像、及び前記第３の像を重ね合わせた第２の電子線ホログラムとを形成することができる。したがって、前記電子線ホログラムから分離して得た前記第１の像及び前記第２の像の再生像を３次元画像表示装置上に表示することにより、前記部分の立体表示を簡易に実現することができ、前記試料面の立体観察を簡易に行なうことができるようになる。
【００１１】
なお、「電子線台形プリズム」とは、一対のフィラメント及びこの一対のフィラメントの外方に設けられた一対のアース電極間の電位分布が台形状となるために、便宜上呼称しているものである。
【００１２】
なお、前記偏向装置は、前記電子線台形プリズムの代わりに偏向板を含み、前記偏向板に印加する電圧の極性を切り替えることにより、前記電子線の偏向方向を変化させ、前記第１の電子線及び前記第２の電子線を形成するようにすることもできる。これによって、前記試料面の同一部分に対して異なる角度で照射すべき、前記第１の電子線及び前記第２の電子線を簡易に形成することができる。したがって、前記試料面の立体観察を簡易に行なうことができるようになる。
【００１３】
【発明の実施の形態】
以下、本発明を発明の実施の形態に基づいて詳細に説明する。
図１は、本発明の透過型電子顕微鏡における一態様の構成を概略的に示す図である。図１に示す透過型電子顕微鏡１０は、電子線照射源１、並びにこの電子線照射源１の前方に順次に設けられた偏向板２、照射レンズ３、結像レンズ４及び撮像素子６を具えている。撮像素子６はステレオ表示モニタ８に接続されている。また、観察すべき試料Ｓは照射レンズ３及び結像レンズ４間に配置されている。
【００１４】
電子線照射源１から発せられた電子線は、偏向板２を通過する際に偏向板２に印加された電圧によって左方向に偏向され、その結果第１の電子線Ｅ１が形成される。第１の電子線Ｅ１は試料Ｓの所定部分に角度θ１で照射される。次いで、偏向板２に印加する電圧の極性を切り替えることにより、電子線照射源１から発せられた前記電子線は右方向に偏向され、その結果第２の電子線Ｅ２が形成される。
【００１５】
第１の電子線Ｅ１及び第２の電子線Ｅ２は試料Ｓを透過し、第１の電子線Ｅ１による試料Ｓの第１の像及び第２の電子線Ｅ２による試料Ｓの第２の像は、それぞれ結像レンズ４を通過して、撮像素子６で撮像される。次いで、前記第１の像及び前記第２の像に相当する電気信号がステレオ表示モニタ８に送信される。モニタ８においては、前記第１の像及び前記第２の像を結合し、試料Ｓの前記所定部分の画像が立体的に表示され、結果として前記所定部分の立体観察を行なうことができる。
【００１６】
図１に示す透過型電子顕微鏡において、前記試料面の観察に要するタクトタイムは前記第１の電子線及び前記第２の電子線の、前記試料面に対する照射時期のずれ（時間間隔）に依存する。そして、この時間間隔は、偏向板２に対する印加電圧の極性の切り替え時間に相当する。したがって、前記電圧極性の切り替えを所定の外部信号などと同期させて行なうことにより、前記時間間隔を極めて短く、例えば１００分の１秒オーダ程度まで簡易に低減することができる。したがって、試料Ｓの前記所定部分の立体観察を実時間で行なうことができる。
【００１７】
なお、前記電圧極性の切り替えは、撮像素子６に対する操作信号と同期させることができる。この場合、第１の電子線Ｅ１による前記第１の像及び第２の電子線Ｅ２による前記第２の像を、それぞれ撮像素子６のフレーム毎に簡易に取り込むことができるようになる。したがって、同一フレーム中に前記第１の像及び前記第２の像が同時に取り込まれたり、前記第１の像及び前記第２の像を取り込まないフレームの出現を回避することができるため、立体観察をより正確に行なうことができるようになる。
【００１８】
また、試料Ｓに対する第１の電子線Ｅ１の照射角度θ１は、試料Ｓの前記所定部分に立てた法線から１度〜５度の範囲に設定することが好ましい。また、試料Ｓに対する第２の電子線Ｅ２の照射角度θ２は、前記法線から１度〜５度の範囲に設定することが好ましい。これによって、試料Ｓの前記所定部分の立体画像を制度良く得ることができ、立体観察を高精度に行なうことができるようになる。
【００１９】
図２は、図１に示す透過型電子顕微鏡の変形例を示す構成図である。図１に示す透過型電子顕微鏡１０においては、偏向板２と試料Ｓとの間に照射レンズ３を配置しているが、図２に示す透過型電子顕微鏡１０−１においては、電子線照射源１と偏向板２との間に照射レンズ３を配置している。
【００２０】
図１及び図２から明らかなように、照射レンズ３を偏向板２と試料Ｓとの間に配置した場合においては、単一の偏向板２を準備するのみで電子線照射源１からの電子線を偏向することができるが、照射レンズ３を電子線照射源１と偏向板２との間に設けた場合においては、２組の偏向板２−１及び２−２を準備して電子線照射源１からの電子線を偏向する。システムの構成を簡易化するという観点からは、図１に示すような構成のものが好ましい。
【００２１】
図３は、本発明の透過型電子顕微鏡における本質的な態様の構成を概略的に示す図である。図３に示す透過型電子顕微鏡２０は、電子線照射源１１、並びにこの電子線照射源１１の前方に順次に設けられた電子線台形プリズム１２、照射レンズ１３、結像レンズ１４、電子線バイプリズム１５及び撮像素子１６を具えている。撮像素子１６は分離再生回路１７を介してステレオ表示モニタ１８に接続されている。また、観察すべき試料Ｓは照射レンズ１３及び結像レンズ１４間に配置されている。なお、結像レンズ１４及び電子線バイプリズム１５は、結像レンズ系を構成する。
【００２２】
図４は、電子線台形プリズムの構成を示す概略図である。図４に示すように、電子線台形プリズム１２は、一対のフィラメント１２２と、このフィラメント１２２と外方に設けられた一対のアース電極１２３とを具えている。この場合、フィラメント１２２及びアース電極１２３間の電位分布は台形状となる。したがって、電子線台形プリズム１２を用いた場合、一対のフィラメント１２２間の領域Ａを通過する電子線は偏向されず、フィラメント１２２及びアース電極１２３間を通過する電子線のみ、それらの間に発生する電場によって偏向される。
【００２３】
電子線照射源１１から発せられた電子線は、電子線台形プリズム１２の領域Ｂを通過する際に、フィラメント１２２及びアース電極１２３間に発生する電場によって左方向に偏向され、その結果第１の電子線Ｅ１が形成される。第１の電子線Ｅ１は試料Ｓの所定部分に角度θ１で照射される。次いで、フィラメント１２２及びアース電極１２３間に印加する電圧の極性を切り替えることにより、電子線照射源１から発せられた前記電子線は、電子線台形プリズム１２の領域Ｂを通過する際に右方向に偏向され、その結果第２の電子線Ｅ２が形成される。
【００２４】
第１の電子線Ｅ１及び第２の電子線Ｅ２は試料Ｓを透過し、第１の電子線Ｅ１による試料Ｓの第１の像及び第２の電子線Ｅ２による試料Ｓの第２の像は、それぞれ結像レンズ１４を通過して、電子線バイプリズム１５に至る。一方、電子線照射源１１から発せされた第３の電子線Ｅ３は試料Ｓを介さずに進行し、結像レンズ１４を経て電子線バイプリズム１５に至る。次いで、物体波としての前記第１の像及び前記第２の像、並びに参照波としての第３の電子線Ｅ３は、電子線バイプリズム１５でそれぞれ重ね合わされ、電子線ホログラムＨを形成する。
【００２５】
次いで、電子線ホログラムＨは撮像素子１６で撮像され、分離再生回路１７で分離された後、前記第１の像及び前記第２の像がステレオ表示モニタ１８に取り込まれる。その結果、試料Ｓの前記所定部分の画像が立体的に表示され、前記所定部分の立体観察を行なうことができる。
【００２６】
図３に示す透過型電子顕微鏡においても、前記試料面の観察に要するタクトタイムは前記第１の電子線及び前記第２の電子線の、前記試料面に対する照射時期のずれ（時間間隔）に依存する。そして、この時間間隔は、電子線台形プリズム１２のフィラメント１２２及びアース電極１２３間に印加する電圧の極性の切り替え時間に相当する。したがって、前記電圧極性の切り替えを所定の外部信号などと同期させて行なうことにより、前記時間間隔を極めて短く、例えば１００分の１秒オーダ程度まで簡易に低減することができる。したがって、試料Ｓの前記所定部分の立体観察を実時間で行なうことができる。
【００２７】
なお、この場合においても、前記電圧極性の切り替えは、撮像素子１６に対する操作信号と同期させることができ、上述した作用効果を得ることができる。
【００２８】
但し、図３に示す透過型電子顕微鏡においては、前記第１の電子線及び前記第２の電子線の切り替えを外部信号と同期させなくても電子線ホログラムＨを得ることができる。したがって、前述した同期操作を実行しなくても、試料Ｓの所定部分の立体観察を行なうことができる。
【００２９】
また、試料Ｓに対する第１の電子線Ｅ１の照射角度θ１は、試料Ｓの前記所定部分に立てた法線から１度〜５度の範囲に設定することが好ましい。また、試料Ｓに対する第２の電子線Ｅ２の照射角度θ２は、前記法線から１度〜５度の範囲に設定することが好ましい。これによって、試料Ｓの前記所定部分の立体画像を精度良く得ることができ、立体観察を高精度に行なうことができるようになる。
【００３０】
以上、具体例を挙げながら発明の実施の形態に基づいて本発明を詳細に説明してきたが、本発明は上記内容に限定されるものではなく、本発明の範疇を逸脱しない限りにおいてあらゆる変形や変更が可能である。
【００３１】
【発明の効果】
以上説明したように、本発明によれば、試料の変化を実時間で観察できる透過型電子顕微鏡及びこの顕微鏡を用いた立体観察法を提供することができる。
【図面の簡単な説明】
【図１】本発明の透過型電子顕微鏡における一態様の構成を概略的に示す図である。
【図２】図１に示す透過型電子顕微鏡の変形例を示す構成図である。
【図３】本発明の透過型電子顕微鏡における本質的な態様の構成を概略的に示す図である。
【図４】電子線台形プリズムの構成を示す概略図である。
【符号の説明】
１、１１電子線照射源
２、２−１、２−２偏向板
３、１３照射レンズ
４、１４結像レンズ
６、１６撮像素子
８、１０ステレオ表示モニタ
１０、１０−１、２０透過型電子顕微鏡
１２電子線台形プリズム
１５電子線バイプリズム
１７分離再生回路
Ｅ１第１の電子線
Ｅ２第２の電子線
Ｅ３第３の電子線
Ｓ試料
Ｈホログラム[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a transmission electron microscope and a stereoscopic observation method.
[0002]
[Prior art]
Conventionally, as a stereoscopic observation method using a transmission electron microscope, a CT method and a stereo method are widely used. In the CT method, one sample is rotated from 0 degree to 180 degrees, a large number of projection images of a predetermined part of the sample are taken within the angle range, and the obtained image is subjected to computer processing to obtain 3 of the predetermined part. It obtains a dimensional structure and enables stereoscopic observation. In the stereo projection method, a sample is rotated, two images with different inclinations of the sample by a parallax angle are photographed, developed and printed, and then stereoscopically observed by using a stereo viewer or the like.
[0003]
[Problems to be solved by the invention]
However, the CT method requires time for computer processing, and there is a problem that changes in the sample cannot be observed in real time. In addition, in the stereo projection method, in addition to the operation of rotating the sample, operations of development and printing are added, and these series of operations require several tens of minutes. There was a problem that it could not be observed in time.
[0004]
An object of this invention is to provide the transmission electron microscope which can observe the change of a sample in real time, and the three-dimensional observation method using this microscope.
[0005]
[Means for Solving the Problems]
In order to achieve the above object, the present invention provides:
An electron beam irradiation source;
A first electron beam provided in front of the electron beam irradiation source and obtained by deflecting the electron beam emitted from the electron beam irradiation source is irradiated at a first angle with respect to a predetermined portion of the sample surface. And irradiating a second electron beam obtained by deflecting the electron beam emitted from the electron beam irradiation source at a second angle different from the first angle with respect to the predetermined portion of the sample surface. A deflection device for causing
The second image by binding of the first of the first image and the second electron beam by an electron beam, comprising a three-dimensional image display device stereoscopically displays an image of the predetermined portion of the sample surface ,
The deflection device includes an electron beam trapezoidal prism including a pair of filaments and a pair of ground electrodes provided outside the pair of filaments,
Furthermore, between the electron beam irradiation source, the electron beam trapezoidal prism, and the three-dimensional image display device, the first image generated by the first electron beam and the first beam emitted from the electron beam irradiation source. The first electron beam hologram obtained by superimposing the third image obtained without passing through the sample surface with the three electron beams, the second image by the second electron beam, and the third image The present invention relates to a transmission electron microscope comprising an imaging device for forming a second electron beam hologram on which the two are superimposed .
[0006]
The present invention also provides:
Emitting an electron beam from an electron beam irradiation source;
A first electron beam obtained by deflecting the electron beam by a deflecting device provided in front of the electron beam irradiation source is irradiated at a first angle to a predetermined portion of the sample surface, and by the deflecting device. Irradiating a second electron beam obtained by deflecting the electron beam at a second angle different from the first angle with respect to the predetermined portion of the sample surface;
The three-dimensional image display device combines the first image obtained by the first electron beam and the second image obtained by the second electron beam to obtain an image of the predetermined portion on the sample surface. Including a three-dimensional display process ,
The deflection device includes an electron beam trapezoidal prism including a pair of filaments and a pair of ground electrodes provided outside the pair of filaments, and switching the polarity of the voltage applied to the filaments allows the electrons to be switched. Changing the deflection direction of the line, forming the first electron beam and the second electron beam;
Furthermore, an imaging device is provided between the electron beam irradiation source, the electron beam trapezoidal prism, and the three-dimensional image display device, and the first image by the first electron beam and the electron beam irradiation. A first electron beam hologram in which a third image obtained without passing through the sample surface is superimposed by a third electron beam emitted from a source, and the second image by the second electron beam, And a method of forming a second electron beam hologram formed by superimposing the third images, and a stereoscopic observation method.
[0007]
The inventors of the present invention have intensively studied to achieve the above object. As a result, two types of electron beams are formed by deflecting an electron beam emitted from a predetermined electron beam irradiation source, and are incident on the same part of the sample surface at different angles, respectively. It has been found that by obtaining two corresponding images and combining them, the portion of the sample surface can be observed three-dimensionally. That is, since the two types of electron beams are irradiated to the portion of the sample surface at different angles, the two types of images are different from each other in two parallax angles corresponding to the angles. It corresponds to. Therefore, if these images are combined and displayed on a predetermined three-dimensional image display device, the part can be displayed in 3D and can be viewed in 3D.
[0008]
In addition, according to the present invention, complicated computer processing such as the CT method described above is not required, and further, operations such as development and baking are not required as in the stereo projection method. The tact time required for this depends on the irradiation timing shift (time interval) of the first electron beam and the second electron beam with respect to the sample surface. However, the deviation of the irradiation time can be reduced as much as possible, and can be easily reduced to the order of 1/100 second by synchronizing with a predetermined external signal or the like. Therefore, the observation of the sample surface can be executed in real time.
[0009]
In the present invention , the deflecting device includes an electron beam trapezoidal prism including a pair of filaments and a pair of ground electrodes provided outside the pair of filaments, and the polarity of a voltage applied to the filament is set. By switching, the deflection direction of the electron beam is changed to form the first electron beam and the second electron beam. This makes it possible to easily form the first electron beam and the second electron beam to be irradiated at different angles with respect to the same portion of the sample surface. Therefore, the stereoscopic observation of the sample surface can be easily performed.
[0010]
Furthermore, by providing an imaging device in front of the electron beam irradiation source and the electron beam trapezoidal prism, the first image generated by the first electron beam and a third beam emitted from the electron beam irradiation source. The first electron beam hologram obtained by superimposing the third image obtained without passing through the sample surface by the electron beam, the second image by the second electron beam, and the third image are superimposed. A combined second electron beam hologram can be formed. Therefore, by displaying the reproduced images of the first image and the second image obtained by separating from the electron beam hologram on a three-dimensional image display device, it is possible to easily realize stereoscopic display of the portion. Thus, the three-dimensional observation of the sample surface can be easily performed.
[0011]
The “electron beam trapezoidal prism” is referred to for convenience because the potential distribution between a pair of filaments and a pair of ground electrodes provided outside the pair of filaments has a trapezoidal shape. .
[0012]
The deflecting device includes a deflecting plate instead of the electron trapezoidal prism, and changes a deflection direction of the electron beam by switching a polarity of a voltage applied to the deflecting plate, so that the first electron beam The second electron beam may be formed. This makes it possible to easily form the first electron beam and the second electron beam to be irradiated at different angles with respect to the same portion of the sample surface. Therefore, the stereoscopic observation of the sample surface can be easily performed.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the present invention will be described in detail based on embodiments of the invention.
FIG. 1 is a diagram schematically showing a configuration of one aspect of a transmission electron microscope of the present invention. A transmission electron microscope 10 shown in FIG. 1 includes an electron beam irradiation source 1, and a deflection plate 2, an irradiation lens 3, an imaging lens 4, and an imaging element 6 that are sequentially provided in front of the electron beam irradiation source 1. It is. The image sensor 6 is connected to a stereo display monitor 8. Further, the sample S to be observed is disposed between the irradiation lens 3 and the imaging lens 4.
[0014]
The electron beam emitted from the electron beam irradiation source 1 is deflected leftward by the voltage applied to the deflection plate 2 when passing through the deflection plate 2, and as a result, the first electron beam E1 is formed. The first electron beam E1 is applied to a predetermined portion of the sample S at an angle θ1. Next, by switching the polarity of the voltage applied to the deflection plate 2, the electron beam emitted from the electron beam irradiation source 1 is deflected in the right direction, and as a result, a second electron beam E2 is formed.
[0015]
The first electron beam E1 and the second electron beam E2 are transmitted through the sample S, and the first image of the sample S by the first electron beam E1 and the second image of the sample S by the second electron beam E2 are Then, each image passes through the imaging lens 4 and is imaged by the image sensor 6. Next, electrical signals corresponding to the first image and the second image are transmitted to the stereo display monitor 8. In the monitor 8, the first image and the second image are combined, and the image of the predetermined portion of the sample S is displayed three-dimensionally. As a result, the predetermined portion can be stereoscopically observed.
[0016]
In the transmission electron microscope shown in FIG. 1, the tact time required for the observation of the sample surface depends on the deviation (time interval) of the irradiation timing of the first electron beam and the second electron beam with respect to the sample surface. . This time interval corresponds to the switching time of the polarity of the voltage applied to the deflection plate 2. Therefore, by switching the voltage polarity in synchronism with a predetermined external signal or the like, the time interval can be shortened to an extremely short time, for example, on the order of 1/100 second. Therefore, stereoscopic observation of the predetermined portion of the sample S can be performed in real time.
[0017]
The voltage polarity switching can be synchronized with an operation signal for the image sensor 6. In this case, the first image by the first electron beam E1 and the second image by the second electron beam E2 can be easily captured for each frame of the imaging device 6, respectively. Accordingly, the first image and the second image can be captured simultaneously in the same frame, or the appearance of a frame that does not capture the first image and the second image can be avoided, so that stereoscopic observation can be avoided. Can be performed more accurately.
[0018]
In addition, the irradiation angle θ1 of the first electron beam E1 with respect to the sample S is preferably set in a range of 1 degree to 5 degrees from a normal line standing on the predetermined portion of the sample S. Moreover, it is preferable that the irradiation angle θ2 of the second electron beam E2 with respect to the sample S is set in a range of 1 degree to 5 degrees from the normal line. As a result, a three-dimensional image of the predetermined portion of the sample S can be obtained systematically, and three-dimensional observation can be performed with high accuracy.
[0019]
FIG. 2 is a configuration diagram showing a modification of the transmission electron microscope shown in FIG. In the transmission electron microscope 10 shown in FIG. 1, the irradiation lens 3 is disposed between the deflecting plate 2 and the sample S. In the transmission electron microscope 10-1 shown in FIG. An irradiation lens 3 is arranged between 1 and the deflection plate 2.
[0020]
As can be seen from FIGS. 1 and 2, when the irradiation lens 3 is arranged between the deflection plate 2 and the sample S, the electrons from the electron beam irradiation source 1 can be obtained only by preparing a single deflection plate 2. In the case where the irradiation lens 3 is provided between the electron beam irradiation source 1 and the deflection plate 2, two sets of deflection plates 2-1 and 2-2 are prepared and the electron beam is deflected. The electron beam from the irradiation source 1 is deflected. From the viewpoint of simplifying the system configuration, the configuration as shown in FIG. 1 is preferable.
[0021]
FIG. 3 is a diagram schematically showing a configuration of an essential aspect in the transmission electron microscope of the present invention. A transmission electron microscope 20 shown in FIG. 3 includes an electron beam irradiation source 11, an electron beam trapezoidal prism 12, an irradiation lens 13, an imaging lens 14, and an electron beam beam provided sequentially in front of the electron beam irradiation source 11. A prism 15 and an image sensor 16 are provided. The image sensor 16 is connected to a stereo display monitor 18 via a separation / reproduction circuit 17. Further, the sample S to be observed is disposed between the irradiation lens 13 and the imaging lens 14. The imaging lens 14 and the electron biprism 15 constitute an imaging lens system.
[0022]
FIG. 4 is a schematic diagram showing the configuration of the electron beam trapezoidal prism. As shown in FIG. 4, the electron beam trapezoidal prism 12 includes a pair of filaments 122 and a pair of earth electrodes 123 provided on the outside of the filaments 122. In this case, the potential distribution between the filament 122 and the ground electrode 123 is trapezoidal. Accordingly, when the electron beam trapezoidal prism 12 is used, the electron beam passing through the region A between the pair of filaments 122 is not deflected, and only the electron beam passing between the filament 122 and the ground electrode 123 is generated between them. Deflected by an electric field.
[0023]
The electron beam emitted from the electron beam irradiation source 11 is deflected to the left by the electric field generated between the filament 122 and the ground electrode 123 when passing through the region B of the electron beam trapezoidal prism 12, and as a result, the first An electron beam E1 is formed. The first electron beam E1 is applied to a predetermined portion of the sample S at an angle θ1. Next, by switching the polarity of the voltage applied between the filament 122 and the ground electrode 123, the electron beam emitted from the electron beam irradiation source 1 moves to the right when passing through the region B of the electron beam trapezoidal prism 12. As a result, the second electron beam E2 is formed.
[0024]
The first electron beam E1 and the second electron beam E2 are transmitted through the sample S, and the first image of the sample S by the first electron beam E1 and the second image of the sample S by the second electron beam E2 are Each passes through the imaging lens 14 and reaches the electron biprism 15. On the other hand, the third electron beam E3 emitted from the electron beam irradiation source 11 proceeds without passing through the sample S, and reaches the electron biprism 15 through the imaging lens 14. Next, the first image and the second image as the object wave and the third electron beam E3 as the reference wave are respectively superimposed by the electron biprism 15 to form an electron beam hologram H.
[0025]
Next, the electron beam hologram H is picked up by the image pickup device 16 and separated by the separation / reproduction circuit 17, and then the first image and the second image are taken into the stereo display monitor 18. As a result, the image of the predetermined portion of the sample S is displayed in a three-dimensional manner, and the three-dimensional observation of the predetermined portion can be performed.
[0026]
Also in the transmission electron microscope shown in FIG. 3, the tact time required for observation of the sample surface depends on the deviation (time interval) of the irradiation timing of the first electron beam and the second electron beam with respect to the sample surface. To do. This time interval corresponds to the switching time of the polarity of the voltage applied between the filament 122 and the ground electrode 123 of the electron beam trapezoidal prism 12. Therefore, by switching the voltage polarity in synchronism with a predetermined external signal or the like, the time interval can be shortened to an extremely short time, for example, on the order of 1/100 second. Therefore, stereoscopic observation of the predetermined portion of the sample S can be performed in real time.
[0027]
In this case as well, the switching of the voltage polarity can be synchronized with the operation signal for the image sensor 16, and the above-described effects can be obtained.
[0028]
However, in the transmission electron microscope shown in FIG. 3, the electron beam hologram H can be obtained without synchronizing the switching of the first electron beam and the second electron beam with an external signal. Therefore, it is possible to perform stereoscopic observation of a predetermined portion of the sample S without performing the above-described synchronization operation.
[0029]
In addition, the irradiation angle θ1 of the first electron beam E1 with respect to the sample S is preferably set in a range of 1 degree to 5 degrees from a normal line standing on the predetermined portion of the sample S. Moreover, it is preferable that the irradiation angle θ2 of the second electron beam E2 with respect to the sample S is set in a range of 1 degree to 5 degrees from the normal line. As a result, a stereoscopic image of the predetermined portion of the sample S can be obtained with high accuracy, and stereoscopic observation can be performed with high accuracy.
[0030]
As described above, the present invention has been described in detail based on the embodiments of the present invention with specific examples. However, the present invention is not limited to the above contents, and all modifications and changes are made without departing from the scope of the present invention. It can be changed.
[0031]
【The invention's effect】
As described above, according to the present invention, it is possible to provide a transmission electron microscope capable of observing changes in a sample in real time and a stereoscopic observation method using this microscope.
[Brief description of the drawings]
FIG. 1 is a diagram schematically showing a configuration of one aspect of a transmission electron microscope of the present invention.
FIG. 2 is a configuration diagram showing a modification of the transmission electron microscope shown in FIG. 1;
FIG. 3 is a diagram schematically showing a configuration of an essential aspect in a transmission electron microscope of the present invention.
FIG. 4 is a schematic diagram showing a configuration of an electron beam trapezoidal prism.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1,11 Electron beam irradiation source 2,2-1,2-2 Deflection plate 3,13 Irradiation lens 4,14 Imaging lens 6,16 Image pick-up element 8,10 Stereo display monitor 10,10-1,20 Transmission type electron Microscope 12 Electron beam trapezoidal prism 15 Electron beam biprism 17 Separation / reproduction circuit E1 First electron beam E2 Second electron beam E3 Third electron beam S Sample H Hologram

Claims

An electron beam irradiation source;
A first electron beam provided in front of the electron beam irradiation source and obtained by deflecting the electron beam emitted from the electron beam irradiation source is irradiated at a first angle with respect to a predetermined portion of the sample surface. And irradiating a second electron beam obtained by deflecting the electron beam emitted from the electron beam irradiation source at a second angle different from the first angle with respect to the predetermined portion of the sample surface. A deflection device for causing
The second image by binding of the first of the first image and the second electron beam by an electron beam, comprising a three-dimensional image display device stereoscopically displays an image of the predetermined portion of the sample surface ,
The deflection device includes an electron beam trapezoidal prism including a pair of filaments and a pair of ground electrodes provided outside the pair of filaments,
Furthermore, between the electron beam irradiation source, the electron beam trapezoidal prism, and the three-dimensional image display device, the first image generated by the first electron beam and the first beam emitted from the electron beam irradiation source. The first electron beam hologram obtained by superimposing the third image obtained without passing through the sample surface with the three electron beams, the second image by the second electron beam, and the third image A transmission electron microscope comprising an imaging device for forming a second electron beam hologram on which the two are superimposed .

The first angle is set to 1 degree to 5 degrees on the right side from the normal direction of the sample surface, and the second angle is set to 1 degree to 5 degrees on the left side from the normal direction of the sample surface. The transmission electron microscope according to claim 1 , wherein the transmission electron microscope is set as follows.

The imaging device according to claim 1 or 2 , further comprising an imaging device for imaging the electron beam hologram on a side opposite to the electron beam irradiation source and the electron beam trapezoidal prism of the imaging device. Transmission electron microscope.

The irradiation timing of the first electron beam to the predetermined portion of the sample surface and the irradiation timing of the second electron beam to the predetermined portion of the sample surface are synchronized with the operation signal of the imaging device. The transmission electron microscope according to any one of claims 1 to 3, wherein:

The first, characterized in that the electron beam hologram and the second electron beam hologram comprises a separation recovery circuit for separating reproduction, transmission electron microscope according to any one of claims 1 to 4.

Emitting an electron beam from an electron beam irradiation source;
A first electron beam obtained by deflecting the electron beam by a deflecting device provided in front of the electron beam irradiation source is irradiated at a first angle to a predetermined portion of the sample surface, and by the deflecting device. Irradiating a second electron beam obtained by deflecting the electron beam at a second angle different from the first angle with respect to the predetermined portion of the sample surface;
The three-dimensional image display device combines the first image obtained by the first electron beam and the second image obtained by the second electron beam to obtain an image of the predetermined portion on the sample surface. Including a three-dimensional display process ,
The deflection device includes an electron beam trapezoidal prism including a pair of filaments and a pair of ground electrodes provided outside the pair of filaments, and switching the polarity of the voltage applied to the filaments allows the electrons to be switched. Changing the deflection direction of the line, forming the first electron beam and the second electron beam;
Furthermore, an imaging device is provided between the electron beam irradiation source, the electron beam trapezoidal prism, and the three-dimensional image display device, and the first image by the first electron beam and the electron beam irradiation source. A first electron beam hologram obtained by superimposing a third image obtained without passing through the sample surface by a third electron beam emitted from the second electron beam, and the second image by the second electron beam, and A stereoscopic observation method comprising a step of forming a second electron beam hologram on which the third image is superimposed .

The first angle is set to 1 degree to 5 degrees on the right side from the normal direction of the sample surface, and the second angle is set to 1 degree to 5 degrees on the left side from the normal direction of the sample surface. The stereoscopic observation method according to claim 6 , wherein the stereoscopic observation method is set as follows.

8. The method according to claim 6 , further comprising a step of imaging the electron beam hologram by providing an imaging element on an opposite side of the imaging apparatus with respect to the electron beam irradiation source and the electron beam trapezoidal prism. Stereoscopic observation method.

A step of synchronizing the irradiation timing of the first electron beam to the predetermined portion of the sample surface and the irradiation timing of the second electron beam to the predetermined portion of the sample surface with an operation signal of the imaging device; The stereoscopic observation method according to any one of claims 6 to 8, wherein the stereoscopic observation method is included.

Said first electron beam hologram, after separation reproduced in said second electron beam hologram and the separation reproducing circuit, and wherein the sterically displayed by the three-dimensional image display apparatus, according to claim 6-9 The stereoscopic observation method according to any one of the above.